This invention relates to optical systems and in particular to an optical system for use in a photocopying environment for scanning an object and incrementally projecting a composite image of the same at an image surface, such as a xerographic or other photosensitive surface.
There are three general types of strip scanning arrangements known to the prior art. In one type, the optical system is fixed and the object and image surface move relative to the optics. In another type, the object is fixed, and the optical system and image surface move at appropriate speeds relative to the object. In a third type, the object is fixed and is scanned by a rotating mirror to relay an image of the object onto a moving image surface.
The present invention is a combination of the first and second types enumerated above. That is, it is capable of operation with a fixed object and moving optics, and conversely with fixed optics and a moving object. The background of this invention will best be understood by reference to U.S. Pat. No. 3,832,057 issued Aug. 27, 1974 to David K. Shogren, the disclosure of which is incorporated herein by reference. Briefly, the referenced patent discloses an optical system having a stationary object platen with a moving optical system for scanning across the platen to create a flowing image of the object supported thereon. This flowing image is projected onto a synchronously moving image surface. The moving optical system includes a first reflector scanning across the object platen at a first rate of speed, and a second reflector scanning in the same direction across the platen at half speed. The object conjugate remains constant due to the differential displacements of the first and second reflectors. Light from the object propagates to the image surface by means of the first reflector, the second reflector, a reflector lens which includes a lens and adjacent reflector, and an image reflector. The lens, lens reflector, and image reflector remain fixed so that the image conjugate is constant. This system is represented in FIG. 1.
It is an object of the present invention to provide an optical scanning system of the type described which is capable of operation at various magnifications.
Another object of this invention is to provide an optical scanning system of the type described which is capable of operation with a fixed object and moving optics or conversely with moving objects and fixed optics.
Other objects, advantages, and features of this invention will become apparent from the following description thereof, taken in connection with the accompanying drawings.